New struts, still a grinding sound. Sway bar bushing?

[StageLeft]

I made a thread a while ago but it's become cluttered and the problem is now narrowed.

2004 Mazda MPV with brand new struts, strut bearings, strut mounts.

Problem: When turning sharply at low speeds (under 10 mph) only to the right, there is a kind of scraping metalic sound from the front somewhere.

Ways to reproduce problem:
1) Turn sharply at very low speed to the right.
2) Less often, but definitely the same sound, with car unmoving rock back and forth in driver's seat. This seems unable to reproduce it now that the struts are changed, perhaps because they are tighter. Also, the sound itself is less noticeable than it was before.

Since this can occur without wheel movement when the car is stopped, it is not brakes. It's definitely not strut related now, either, so it narrows down and it sure seems it must be suspension related, since it occurs when the car rocks back and forth.

Left bushing

The right bushing looked similar, at least from the outside.

I'm very close to bringing this in, but I really hate to do that.

 

[Mxylplyx]

Another thought may be the dust shield behind your rotors interfering with something. Check that out.

 

[radioouman]

How about a wheel bearing?

 

[Pacfanweb]

Definitely could be the sway bar bushings, or even the end links if it has them. Lube the hell out of them with something runny, like WD40. That isn't typically what you'd want for a lasting lubricant, but for seeing if that is the problem, QUICKLY, it will work.

The rack also has bushings. Might want to lube them, too, but do the sway bar bushings first.

 

[boomerang]

Since this can occur without wheel movement when the car is stopped, it is not brakes. It's definitely not strut related now, either, so it narrows down and it sure seems it must be suspension related, since it occurs when the car rocks back and forth.

Can you lay down in front of the car and have someone else rock the car? It should be easier to pinpoint being up close to it.

You can disconnect that sway bar at the struts (if I remember your last set of pictures) and take that out of the mix when you have the car rocked. I'd say there's a good chance that the bushing you have pictured needs some lube. Do both driver and passenger sides. Don't use a petroleum based grease. Petroleum products rot rubber.

It could be lower control arm mounts, steering rack mounts, or, if the engine cradle is rubber mounted to the body, that's a possibility too. Obviously, I'm thinking it's a rubber mount/bushing issue.

Laying under it and having it rocked should allow you to narrow it down.

 

[kevman]

Did you check for any axial play on your wheels when they were on the jack stands ? Could be a hub or bearing, I had the same issue on one of my corners.

 

[StageLeft]

Thanks for the ideas. I did check for wheel play and noticed none. The problem with rocking is it's so hard to repeat it in that manner, but if I can then I will need to get under the car and see exactly what's doing it. I've thought of putting a recording device around there, too, but it probably won't be directional enough.

Is there an easy way to check for brake rub, on the off chance it is the culprit? It does sound like it, but since it's happened with the car unmoving and the brakes are new, it would only be that if the caliper was messed.

Also, it is safe to drive without the sway bar, isn't it; I mean I can take its links out and if the sound is still there I know that the sway bar is good...

 

[boomerang]

You most certainly can unhook the sway bar. You will want to make sure you secure the bar so it doesn't rotate and interfere with another suspension components when you drive.

The car will just lean more in turns. A disconnect and a short drive should tell the tale.

A wheel bearing is not going to make noise just rocking the car back and forth. You've checked those and I'd rule them out. IMO it's highly unlikely it's brakes. You could of course remove the pads, bolt the calipers and wheels back on and rock 'till you drop. A lot of dicking around. A waste of time IMO. If you do this, be sure not to press on the brake pedal with the pads off.

Myself, I'd just remove those sway bar bushings, clean up the bars, grease the bushings and reassemble. Although there's nothing wrong with doing a true diagnosis.

 

[AMCRambler]

My first guess would be sway bar mounts or end links or maybe the ball joints. It sounds like the issue occurs when the suspension is compressed. If you've replaced the entire strut assembly and mounts then the only other pieces moving as the suspension flexes would be the sway bar, lower control arm and the ball joints. If it was a sway bar bushing, then you'd notice the car pulling to one side when braking.
Sway bar definitely gets worked when you corner hard or sit in the car and rock it back and forth. You could have a mounting bracket that has busted loose where the sway bar is bolted to the frame. You'd have to look close at it if only one of the bolts holding it in snapped.
The last thing I'm thinking of would be the ball joints. Usually when those wear you'll see issues with tread wear on the front wheels though. The insides will wear more than the outside. The grinding could also be the post of the ball joint slipping against the pinch bolt in the knuckle. That would be a bad thing, but usually those don't slip though.

 

[StageLeft]

Cool. I think next up is a complete disconnect of the sway bar links (one is brand new, the other is not, fwiw) so that the sway bar is just hanging there by itself (I'll make sure it doesn't get in the way of anything, though). If the links are out of the picture, the sway bar will serve absolutely no purpose, right? So, if the bushings are bad, I will not hear any sound because they're under no stress and then I'll know what the cause is.

 

[boomerang]

Originally posted by: Skoorb
Cool. I think next up is a complete disconnect of the sway bar links (one is brand new, the other is not, fwiw) so that the sway bar is just hanging there by itself (I'll make sure it doesn't get in the way of anything, though). If the links are out of the picture, the sway bar will serve absolutely no purpose, right? So, if the bushings are bad, I will not hear any sound because they're under no stress and then I'll know what the cause is.

Zactly right.

 

[exdeath]

Sources of noise in suspension:

ball joints
struts (esp if dust boot shows signs of old damage)
upper strut mounts (usually rubber donuts)
spring isolators, upper and lower if present (rubber disks or tube around the first coil between spring and metal)
control arm bushings
steering rack bushings
tie rod ends
sway bar bushings
sway bar end links
motor and transmission mounts

Other than that, make sure everything above is torqued to spec and check for signs of metal-metal wear as a result of loose bolts.

The sway bar bushings don't typically come into play unless the wheels are on uneven surfaces. A drive on lift is convenient, have someone else get in the car while it's in the air and rock it and turn the wheel lock to lock while you walk around under the car. Helps if you not only listen, but put your hand on things and feel for the source of the noise.

In the picture you show the sway bar bushing looks fine, thought it could probably use some grease. Sway bar should freely rotate in the chassis bushings without binding.

My bet is on the rack bushings if it only makes the sound when you turn the wheel one way. Seems like the rack binds up when you turn one way, then releases the tension when you turn the other way, and making noises in the process. But that's usually described as more of a creaking or popping noise not grinding. Hard to say without hearing it in person.

Think about the things that are moving or being loaded when you are parked on a level surface, not rolling, and turning the wheel (engine off I assume?) and follow the forces:
steering shaft -> rack -> rack-frame interface -> tie rod/knuckle interface -> ball joint -> control arm (not up and down, but in plane as ball joint leverages) -> control arm-frame interface. Also have the strut rotating with the knuckle and the CV joint bending. Has to be one of those things.

 

[Pacfanweb]

ex, the sway bar is used to prevent body roll, which is what happens in turns, which is when he's hearing the noise. So they are a definite possibility.

I agree about the rack bushings, and mentioned it earlier in this thread....the rack bushings get the most pressure of all when turning.

 

[alkemyst]

Originally posted by: boomerang
Can you lay down in front of the car and have someone else rock the car? It should be easier to pinpoint being up close to it.

QFT, should have been the first test since you knew it also happened not moving.

 

[StageLeft]

Originally posted by: alkemyst

Originally posted by: boomerang
Can you lay down in front of the car and have someone else rock the car? It should be easier to pinpoint being up close to it.

QFT, should have been the first test since you knew it also happened not moving.

I was going to and it is a good QFT but it was not always reproducible and I was getting pressure to get it repaired and to "bring it in somewhere", so I just went ahead and "fixed it".

I'll say, it's MUCH better, it truly is. It's still there, but it's better. I can only assume the new struts are stiffer and not allowing as much shifting or rolling, because it's only there now when you know what you're looking for.

If I can get some time this weekend (probably can!), I'll unhook the sway bar and see how things are.

 

[tyler811]

Originally posted by: radioouman
How about a wheel bearing?

My thought too

 

[exdeath]

Originally posted by: Pacfanweb
ex, the sway bar is used to prevent body roll, which is what happens in turns, which is when he's hearing the noise. So they are a definite possibility.

I agree about the rack bushings, and mentioned it earlier in this thread....the rack bushings get the most pressure of all when turning.

Body roll only occurs in motion or parked on an uneven surface when he control arms are at different distances from the body; the sway bar wont be loaded simply turning the wheel on a level surface while parked.

Most common time someone hears the creaks and clunks of bad sway bar bushings is going over a speed bump at an angle or while turning continuously (eg: banked off ramp) while hitting bumps and cracks in the road.

It's pretty hard to replicate that parked and level, but fortunately sway bar bushings are easy to inspect visually.

 

[Pacfanweb]

Problem occurred mostly on sharp turns at low speeds.

Also when rocking the car, which is certainly flexing the swaybar.

I'll agree that most of the time, swaybar problems happen under the conditions you mentioned, but they are still a possibility here.

I'd still check the rack first, but don't rule the swaybar bushings out.

If you work on cars long enough, you'll find out that almost nothing is impossible, even though it theoretically should be.